Prefabricated panel for building construction and process for manufacturing such a panel

ABSTRACT

Prefabricated panel ( 1 ) for building construction that includes a core ( 2 ) that is made of insulating material and that is covered on its two faces by a uniform concrete layer ( 3 A,  3 B), and in which there are provided, close to one face of the plate, housings ( 4 ) for struts ( 5 ) that project at one end for the purpose of sealing them against the ground, and, on the opposite face of the plate, housings ( 7 ) for reinforcement elements ( 8 ) extending between two parallel edges of the panel ( 1 ) and projecting beyond these edges so as to constitute a belt element, in the assembled state of the panel ( 1 ) with adjacent panels ( 21, 22 ). The prefabricated pane is useful for the construction of outer walls of a building with a very light structure.

This invention relates to the field of the construction of buildingsusing prefabricated panels, and it relates more particularly to theprefabricated panel per se, the assembly of several panels together, andthe processes for manufacturing said panels, as well as the constructionof the building using these prefabricated panels.

The important construction quality criteria include especially themechanical strength and heat insulation of the walls that form the outerjacket of the building. These criteria can be met by the use of twomaterials with opposite but complementary properties, which arereinforced concrete and expanded polystyrene.

Actually, on the one hand, reinforced concrete is inexpensive, easy touse, has very good mechanical strength and is nonflammable, but it hasthe drawback of heavy weight and poor heat insulation.

By contrast, expanded polystyrene, which is also inexpensive, hasexcellent heat insulation and very low weight, but it has the drawbackof being inflammable and having a very low mechanical strength.

Among the processes for simultaneous use of these two materials in theconstruction of buildings, it is possible to cite:

A method that consists in mounting polystyrene panels on theconstruction site, in placing a reinforcement around these panels, thenin spraying concrete on each of the faces of the polystyrene panel.

Another method comprises the installation of two parallel polystyrenepanels that are used as a framework, the incorporation of crosspiecesand metal frames, then the pouring of concrete inside the space that isformed by the two panels, and then the coating of the outer faces of thepolystyrene with concrete.

Still another method consists in using polystyrene blocks in the form ofparallelepiped hollow blocks, in placing metal reinforcements inside therecesses of the parallelepiped hollow blocks, and in pouring concreteinto them, whereby the whole is then covered with concrete on theoutside.

The major drawbacks of these methods are as follows. First, during theconstruction, the polystyrene part is visible, which is an importantobstacle to the development of this type of construction becauseexpanded polystyrene, in the mind of the public, is a down-marketmaterial with an image of very low strength. In addition, these wallsare not reproduced in an identical manner since they are manufactured onsite; in particular the coating concrete layer is not uniform and isdifficult to reproduce from one wall to the next, from one constructionproject to the next. In addition, when the expanded polystyrene is usedas a formwork, it is necessary to provide guide elements for theirmounting or frameworks and crosspieces that are at the origin of thermalbridges.

The object of this invention is therefore to eliminate theabove-mentioned drawbacks by proposing a construction process thatcombines the use of reinforced concrete and expanded polystyrene andthat is simple to execute, whereby the creation of thermal bridges thatinterfere with the thermal insulation of the manufactured walls isavoided.

Another object of the invention is to propose a process for theproduction of walls for low-cost and totally reproducible buildings.

For this purpose, it has been considered to design afactory-prefabricated panel that comprises a core made of expandedpolystyrene-type insulating material that is covered on its two faceswith a layer of concrete.

Such panels have been described in particular in the patents DE 3242364or U.S. Pat. No. 4,669,240; however, these modular elements have eithermetal crosspieces for holding the two outer walls of the panel, or metalframeworks that link these two walls together; thermal bridges aretherefore present in these modules.

Likewise, the module that is described in the patent U.S. Pat. No.5,697,189, formed by a concrete panel that is equipped with internalcavities filled with expanded polystyrene, exhibits the drawback thatthe concrete communicates from one face to the next.

These internal concrete bonds are also at the origin of undesirablethermal bridges.

Another object of the invention is therefore to design prefabricatedpanels and an assembly of these panels that is free of thermal bridges,while having high mechanical strength and being very light.

For this purpose, this invention therefore relates first of all to aprefabricated panel for building construction that comprises a core thatis full of insulating material in the form of a plate that is covered onits two faces by a uniform concrete layer, characterized in that in saidplate that forms the core, there are provided:

-   -   On the one hand, close to one face of the plate, a first series        of housings for reinforcement elements constituting struts when        the panel is set up on the ground, whereby at least one of their        ends projects for the purpose of sealing them against the        ground, and    -   On the other hand, on the opposite face of the plate, a second        series of housings for reinforcement elements extending between        two parallel edges of the panel and projecting beyond these        edges so as to constitute a belt element, in the assembled state        of said panel with adjacent panels.

The prefabricated panel that comprises elements for connection withadjacent panels makes it possible to produce, in a very quick period oftime, the construction of buildings whose walls, in particular the outerwalls, consist of such panels. Whereby the two faces of theinsulating-material plate are covered at the factory with a concretelayer, the insulating layer is masked and is not at all visible duringthe construction. Furthermore, whereby the application of concrete canbe carried out flat at the factory, the thickness of these concretelayers is uniform and very reproducible from one panel to the next. Itis therefore possible to ensure—for all the panels—identical propertiesin terms of mechanical strength or thermal insulation, for example.

Advantageously, the first series of housings and the second series ofhousings provided in the plate that forms the core of the panel are freefrom communication zone between them so as to avoid the formation ofthermal bridges. Thus, the reinforcements that are arranged on one faceare separated from the reinforcement elements that are arranged on theother face of the core that is made of insulating material. In addition,there is no communication zone between the two outer layers of concrete.

The housings are advantageously made in the form of grooves whoselongitudinal axes are orthogonal from one series to the next. Thesegrooves can either be flush with the outer surface of the plate made ofinsulating material or come out on the surface of this plate.

The reinforcement elements are preferably metal elements.

A preferably metal trellis can be applied on—or be arranged parallelto—each face of the plate that forms the core of the panel in theimmediate proximity of the latter. Preferably, the reinforcementelements can also be used as a support to this framework. The dimensionsof this trellis advantageously correspond to the surface of each of thefaces of the plate.

So as to be able to assemble the panels between them by forming anangle, it is advantageous that the sections of the panel be at leastpartially beveled to adapt to the adjacent panels by forming an assemblyof the groove-assembly type, whereby the assembly is interrupted toprovide a free-angle zone that allows the belt elements of two adjacentpanels to be connected. In the case where a concrete layer covers thebeveled section, it may be advantageous—to prevent the creation of athermal bridge via the concrete—to provide a discontinuous beveledsection, namely the incorporation of a belt of insulating materialcrosswise to said section.

Preferably, the core is made of preferably high-density expandedpolystyrene or of rigid foam with closed cells.

The faces of the plate that forms the core preferably have striatedsurfaces for a better adhesion of the concrete to the latter.

The thus manufactured panel is inexpensive and has good mechanicalstrength as well as excellent thermal insulation. In addition, wherebythe core may have a significant thickness, this panel has very littleweight relative to the existing prefabricated panels. It is thereforeeasily transportable up to the construction sites. The reduced weight ofthese panels also entrains the limitation of the thickness of thenecessary foundations to support these panels.

This invention also relates to an assembly of prefabricated panels forbuilding construction as described above, whereby the reinforcementelements that extend between two parallel edges of the panel are housedin horizontal grooves made in the core of the panel, on its face turnedtoward the outside of the building, so as—after connection of theprojecting ends of the reinforcement elements of adjacent panels—to forma horizontal framework of the construction, by thus constituting aself-supporting-type structure. Such a structure is stable, rigid andundeformable.

This invention also relates to a process for manufacturing aprefabricated panel as described above, comprising the followingsuccessive stages:

-   -   Cutting of an expanded polystyrene plate by providing, on the        one hand, a first series of grooves that are parallel to one        another on one face of the plate and, on the other hand, a        second series of grooves that are parallel on the other face of        the plate, whereby the longitudinal axes of the grooves are        orthogonal from one series to the next and sections of the plate        are partially beveled,    -   Incorporation of reinforcement elements in their respective        grooves, by allowing their projecting ends beyond the edges of        the plate,    -   Attachment of a preferably metal trellis on each face of the        plate, with hooking of the trellis on the reinforcement        elements, so as to form a reinforced plate,    -   Pouring a uniform layer of self-smoothing concrete on one face        of said reinforced plate and then drying the concrete,    -   Pouring a uniform layer of self-smoothing concrete on the other        face of said reinforced plate, then drying the concrete.

This very simple process can easily be carried out at the factory.

This invention also relates to a process for building construction usingsuch prefabricated panels, including the process for manufacturingabove, and also comprising:

-   -   The vertical placement of each panel and the sealing against the        ground of the projecting ends of the reinforcement elements that        form vertical struts, housings of the belt elements that are        found arranged horizontally on the face of the panel rotated        toward the outside of the building to be constructed,    -   Drawing-together and contact of the beveled sections of adjacent        panels,    -   Installation of the connection between the corresponding        projecting ends of the belt elements that are arranged        horizontally, at the free-angle zones between the adjacent        panels, by creating a complete belt of the construction.

Advantageously, in the free-angle zone between two adjacent panels, apreferably metal vertical framework—with which the projecting ends ofthe horizontal reinforcement elements are made integral—is arranged.

In addition, around the free-angle zone between two adjacent panels, canbe arranged a formwork that makes it possible to pour concrete there.

This construction process is therefore very simple and very quick touse. The thus produced construction is, besides its properties ofmechanical strength and thermal insulation, very inexpensive.

The thus produced walls make it possible to fit standard roofs(frameworks and covers) there and can easily be covered by a standardfinishing coating.

Openings, such as doors and windows, can be arranged in said panel atthe factory. In addition, the plate that is made of insulating materialand that constitutes the core can also be cut or machined so as toprovide sheathing for electric cables or pipes. The only thing left todo on the construction site is to make the connections for these cablesor pipes.

The upper ends of the vertical reinforcement elements can project fromthe upper edge of the panel so as to constitute hooking elements (forexample for towing chains) for the purpose of handling and transport ofsaid panel at the factory or on the construction site. These projectingends can also make possible the attachment or the affixing to said panelof various other construction elements, in particular roof elements.

This invention also relates to a building that is constructed by theprocess above, characterized in that the outer walls consist of anassembly of prefabricated panels as described above.

Other particular features and advantages will emerge from thedescription below of a non-limiting embodiment example of the inventionwith reference to the accompanying figures in which:

FIG. 1 is a longitudinal top view of a panel according to thisinvention;

FIG. 2 is a partial top view of an assembly of three adjacent panelsaccording to this invention;

FIG. 3 is a front view of the assembly according to FIG. 2.

As shown in FIG. 1, a panel according to this invention consists of acore 2, preferably made of expanded polystyrene, sandwiched between twoconcrete layers 3A (outer layer) and 3B (inner layer). The core 2 formsa plate that can itself consist of an assembly of polystyrene blocksthat are glued together, as shown in FIGS. 1 and 3, and referenced 2 a,2 b, 2 c, 2 d . . . (the words “inner” and “outer” refer, in the entiretext, to the positioning of the faces of the panel during theconstruction of the building).

In the plate forming the core 2, close to its inner face, housings 4that are parallel to one another and that consist of grooves (verticalwhen the panel is set up on the ground) are provided. These housings 4,shown here in FIG. 1 as opening on the inner face of the core 2,accommodate metal reinforcements 5 that are kept in place in the housingby wedges (not shown). The inner trellis 6 that is arranged parallel tothe inner face of the core 2 is attached to these verticalreinforcements 4. During the application of self-smoothing concrete onthe inner face of the core 2, this concrete forms the inner concretelayer 3B and also fills the grooves that form housings 4 by embeddingthe framework 6 and the vertical reinforcements 4.

On the outer face of the core 2, housings 7 (horizontal when the panelis set up on the ground) that are designed to accommodate the horizontalreinforcement elements 8 are cut out. An outer trellis 9 is arrangedparallel to the outer face of the plate that forms the core 2. Thistrellis is connected by multiple connections 10 to the horizontalreinforcement elements 8 to keep it in place in particular during thepouring of the concrete, and to separate it (by a small distance) fromthe outer face of the core 2.

When the concrete of layer 3A is poured over the outer face of the core2, this concrete also fills the openings that are left in the housings 7around the reinforcement element 8 and covers the reinforcement element8 and the outer trellis 9.

The spacing of the inner trellis 6 and the outer trellis 9 of therespective faces of the polystyrene plate can also be done using ribs orprojections made on the surface of said plate so that the trellis arealmost entirely covered in the concrete.

The grooves that are used as housing in the metal reinforcements 5 and 8can have various shapes, for example U, T, dovetailed, etc. . . . : theyare also used as molds for the concrete that has been poured there.

To fill said housings and to form the layers that cover each face of thecore 2, the preferably self-smoothing concrete can be cast all at onceor in several times; in this latter case, it is possible to useconcretes of different natures.

The reinforcement elements 5 and 8 can consist of a single rod orprofile, or advantageously, as in the example shown in FIGS. 1 and 2, ofan assembly of several rods (four here) that are connected together bycrosspieces, for example, of the zigzag type, as is the conventionalmethod at construction sites using reinforced concrete.

The vertical sections of the panel 1 are partially beveled 11, here at45°. This beveled form 11 allows the panel 1 to be applied against twoadjacent panels 21 or 22, as can be seen in FIG. 2. The angle zone thatis then left free 12 between two adjacent panels is a space that makesit possible to join the horizontal reinforcement elements of twoadjacent panels and to link them, for example, by welding them to oneanother and/or to a framework 13 that is positioned vertically as shownin FIG. 2. Such a connection between two adjacent panels thusconsiderably solidifies the structure.

After assembling two adjacent panels according to the invention, aformwork 14 can be installed around the angle zone 12 so that theconcrete can be cast into it.

Finally, it is possible to coat the concrete layers 3A and 3B, either atthe factory, or at the end of the construction, by a finishing coating15A and 15B.

As can be seen in FIG. 3, openings 16, 17 can be made in the entirepanel so as to affix it at the factory or on the site respectively ofwindows or doors.

The thus manufactured panel can be easily anchored on the ground 15 inparticular using lower projecting ends 18 of the reinforcement elements5 that form vertical struts and that are connected to constructionelements, such as roofing, by means of upper projecting ends 19 of thesesame reinforcement elements 5, which are also used for hooking duringhandling and for transport of said panel. The horizontal reinforcementelements 8 that form a belt of the construction are arranged—when thereare openings provided for windows or doors—on both sides of theseopenings in the vertical direction.

Each panel can, by itself, constitute the entire wall of a building; theassembly of four panels according to the invention makes it possible toproduce, for example, the four outer walls of a house, thus constructedvery quickly.

The composite walls that are made using panels according to thisinvention are both rigid and light. The thickness of the polystyrenecore can be, for example, on the order of 30 centimeters; the thicknessof the inner and outer concrete layers 3A and 3B can be, for example,between 2 to 3 centimeters, approximately.

Finally, for a better seating and better stability of the panel in theconstruction, longitudinal housings made in the upper and/or lowerhorizontal sections of the panel 1 and designed to accommodate beams,for example made of concrete, can be provided.

Such lay-outs can actually prove useful when the panels are to supportcovers of significant weight.

1. Prefabricated panel (1) for building construction that comprises acore (2) that is full of insulating material in the form of a plate thatis covered on its two faces by a uniform concrete layer (3A, 3B),characterized in that in said plate that forms the core (2), there areprovided: On the one hand, close to one face of the plate, a firstseries of housings (4) for reinforcement elements (5) constitutingstruts when the panel is set up on the ground, whereby at least one oftheir ends (18) projects for the purpose of sealing them against theground, and On the other hand, on the opposite face of the plate, asecond series of housings (7) for reinforcement elements (8) extendingbetween two parallel edges of the panel (1) and projecting beyond theseedges so as to constitute a belt element, in the assembled state of saidpanel (1) with adjacent panels (21, 22).
 2. Panel according to claim 1,wherein the first series of housings (4) and the second series ofhousings (7) are free of communication zone between them so as to avoidthe formation of thermal bridges.
 3. Panel according to claim 1, whereinthe housings (4, 7) are made in the form of grooves whose longitudinalaxes are orthogonal from one series to the next.
 4. Panel according toclaim 1, wherein the reinforcement elements (5, 8) are metal elements.5. Panel according to claim 1, wherein the reinforcement elements (5, 8)are also used as a support to a preferably metal trellis (6, 9),arranged parallel to each face of the plate that forms the core (2) ofthe panel in the immediate proximity of the latter.
 6. Panel accordingto claim 1, wherein the sections (11) of the panel (1) are at leastpartially beveled to adapt to the adjacent panels (21, 22) by forming anassembly of the groove-assembly type, whereby the assembly isinterrupted to provide a free-angle zone (12) that allows the beltelements of two adjacent panels to be connected.
 7. Panel according toclaim 1, wherein the core (2) is made of preferably high-densityexpanded polystyrene.
 8. Panel according to claim 1, wherein the facesof the plate that form the core (2) have striated surfaces for a betteradhesion of the concrete to the latter.
 9. Assembly of prefabricatedpanels for building construction according to claim 1, wherein thereinforcement elements (8) extending between two edges parallel of thepanel (1) are housed in horizontal grooves that are made in the core (2)of the panel, on its face turned toward the outside of the building, soas—after connection of the projecting ends of the reinforcement elementsof adjacent panels—to form a horizontal girdle of the construction, bythus constituting a self-supporting-type structure.
 10. Process formanufacturing a prefabricated panel according to claim 1, comprising thefollowing successive stages: Cutting of an expanded polystyrene plate byproviding, on the one hand, a first series of grooves that are parallelto one another on one face of the plate and, on the other hand, a secondseries of parallel grooves on the other face of the plate, whereby thelongitudinal axes of the grooves are orthogonal from one series to thenext and partially beveled sections of the plate, Incorporation ofreinforcement elements (5, 8) in their respective grooves, by allowingtheir projecting ends beyond the edges of the plate, Attachment of apreferably metal trellis (6, 9) on each face of the plate, with hookingof said framework on the reinforcement elements (5, 8), so as to form areinforced plate, Pouring a uniform layer of self-smoothing concrete onone face of said reinforced plate and then drying the concrete, Pouringa uniform layer of self-smoothing concrete on the other face of saidreinforced plate and then drying the concrete.
 11. Process for buildingconstruction using prefabricated panels according to claim 1, and alsocomprising: The vertical placement of each panel and the sealing againstthe ground of the projecting ends (18) of the reinforcement elements (5)that form vertical struts, housings (7) of the belt elements that arefound arranged horizontally on the face of the panel rotated toward theoutside of the building to be constructed, Drawing-together and contactof the beveled sections (11) of adjacent panels, Installation of theconnection between the corresponding projecting ends of the beltelements that are arranged horizontally, at the free-angle zones (12)between the adjacent panels, by creating a complete belt of theconstruction.
 12. Process according to claim 11, wherein a preferablymetal vertical framework, with which the projecting ends of thehorizontal reinforcement elements (8) are made integral, is arranged inthe free-angle zone (12) between two adjacent panels.
 13. Processaccording to claim 11, wherein a formwork (14) that makes it possible topour the concrete there is arranged around the free-angle zone (12)between two adjacent panels.
 14. Building constructed by the processaccording to claim 11, wherein the outer walls consist of an assembly ofprefabricated panels (1, 21, 22) according to claim
 9. 15. Processaccording to claim 12, wherein a formwork (14) that makes it possible topour the concrete there is arranged around the free-angle zone (12)between two adjacent panels.
 16. Panel according to claim 2, wherein thehousings (4, 7) are made in the form of grooves whose longitudinal axesare orthogonal from one series to the next.